My submission for the next creature vote is the haast eagle, also known as the harpagornis. It went extinct in the 1400's, was the largest eagle that has ever existed with talons the size of tigers claws, and has been credited of being the inspiration behind the legends of giant man eating birds in New Zealand. It was the apex predator of it's environment, and was capable of killing creatures multiple times it's size. It is believed to have killed very large prey by divebombing vulnerable areas, and wrestling it to the ground while slashing with it's massive talons. Given this, I think it could function well as a powerful apex predator of the skies of ark. Ark barely has any birds, and only of a handful of them are actually very useful. Having the haast eagle soaring the skies of the arks mountains and jungles would provide a new powerful flyer that would not only provide a fun way to travel around the map, but also be a useful tame full of utility's depending on what you need.
-Dive bomb attack that can stun flyers mid air for about ten seconds(works on creatures up to the size of a quetzal)
-Wing attack, after soaring/diving for a short amount of time the it will gain the ability to perform a new attack. When landed, a built up wing beat will result in gust of wind that pushes attackers back. Works up to creatures the size of a carno/baryonyx. The resulting hit has the potential to keep several attackers back for several seconds. The wing beat will also collect nearby resources if not being used to attack anything.
-Enhanced agility, able to turn on a dime at high speeds through the trees
-Prime meat collector, can collect prime meat from smaller creatures with it's talons
-Extremely fast speed and damage, counter to it's average stamina/weight
-Insulation, provides warmth from it's feathers when flying through the colder regions of the map
-Does decent damage to armor with it's talons
-A screech that boosts other flyers. Similar to the yuty on land, and it would make sense as large predatory birds like eagles and hawks screech
-Pest Control + Eagle Eye, when set on wander it targets small creatures in a large vicinity like troodons, pegos, dilos, and ichthyornis(this factors into the whole prime meat collector thing)
-The pest control ability would also target non tribemates on foot trying to sneak into your base, so having some of these soaring around base would be very beneficial from getting raided
Taming Method: Either standard tranq and feed, or by collecting eggs from nests in large trees and cliffsides.
Appearance: Appearance loosely based off the largest living forest eagles like harpy, crowned, and philippine eagles, but with obvious differences to give it a distinct, different look. To some extant, it would make sense for it to have some slight resemblance to the little eagle(ironically it's closest living relative). Having a crown of feathers like some other large raptors that could be a color region would also add to it's look. A small detail that should be mentioned was that in real life it had a fairly long beak. (Credit to artist Ben Garrod for the nest art of eagles, it's very accurate in showing the longer hooked beak. He's an amazing paleo artist so credit to him.)
Other Notes: Rideable, can go with or without saddle, although like with almost any creature a saddle is preferred. Smaller then the argent but bulkier/taller then the pelagornis. It would have a slightly shorter wingspan, but more broad and robust wings in general. Posture wise it would stand similar to living eagles, and have a tall upright stance when grounded. Regarding the wing attack, think of the build up being something similar to the woolly rhinos charge. During it's boosting shriek, it's crown of feathers could flare up like a dilo's frill. Spawns with nests in the redwoods, near cliffs, and in the colder areas of the map at higher elevation. Drops feathers(pelt) and talons that can be used for crafting when killed. Most large eagle nests today are full of fur and bones from previous meals, so even if the eggs are the main focus one could collect some pelt or additional resources from nests/empty nests. Extra ideas in the comments are welcome. Also, not ability related but if someone could make a dossier for this it would be greatly appreciated.